﻿// Copyright (c) 2011 João Angelo
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of this 
// software and associated documentation files (the "Software"), to deal in the Software 
// without restriction, including without limitation the rights to use, copy, modify, merge, 
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons 
// to whom the Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or 
// substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR 
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE 
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 
// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR 
// THE USE OR OTHER DEALINGS IN THE SOFTWARE.

namespace Helpers.Web
{
    using System;
    using System.Globalization;
    using System.Reflection;
    using System.Resources;
    using System.Web;
    using System.Web.Caching;
    using System.Web.Compilation;

    public sealed class AssemblyResourceProvider : IResourceProvider
    {
        private object managerSynchLock = new object();

        private AssemblyResourceProvider(ResourceTypeInfo typeInfo)
        {
            if (typeInfo == null)
                throw new ArgumentNullException("typeInfo");

            this.TypeInfo = typeInfo;
        }

        private static Cache Cache
        {
            get { return HttpRuntime.Cache; }
        }

        public static AssemblyResourceProvider GetProvider(ResourceTypeInfo typeInfo)
        {
            const string CacheKeyPrefix = "ProviderFor: ";

            string key = String.Concat(CacheKeyPrefix, typeInfo.AssemblyQualifiedTypeName);

            var provider = Cache[key] as AssemblyResourceProvider;

            if (provider == null)
            {
                provider = new AssemblyResourceProvider(typeInfo);

                Cache.Insert(
                    key, 
                    provider, 
                    null, 
                    Cache.NoAbsoluteExpiration, 
                    TimeSpan.FromMinutes(5));
            }

            return provider;
        }

        public ResourceTypeInfo TypeInfo { get; private set; }

        public object GetObject(string resourceKey, CultureInfo culture)
        {
            this.EnsureResourceManager();

            return this.Manager.GetObject(resourceKey, culture);
        }

        public IResourceReader ResourceReader
        {
            get
            {
                throw new NotSupportedException(
                    "Resource values enumeration is not supported.");
            }
        }

        private ResourceManager Manager { get; set; }

        private void EnsureResourceManager()
        {
            lock (this.managerSynchLock)
            {
                if (this.Manager == null)
                {
                    var assembly = Assembly.Load(this.TypeInfo.AssemblyFullName);

                    this.Manager = new ResourceManager(this.TypeInfo.TypeFullName, assembly);
                }
            }
        }
    }
}
